1. Field of Invention
This invention relates to introducers. More particularly, this invention relates to a guiding introducer system for use within the left atrium of the human heart.
2. Prior Art
Introducers and catheters have been in use for medical procedures for many years. For example, one use has been to convey an electrical stimulus to a selected location within the human body. Another use is the monitoring of measurements for diagnostic tests within the human body. Thus, catheters may be used by a physician to examine, diagnose and treat while positioned at a specific location within the body which are otherwise inaccessible without more invasive procedures. Catheters may be inserted into a major vein or artery which is near the body surface. The catheters are then guided to the specific location for examination, diagnosis or treatment by manipulating the catheter through the artery or vein of the human body.
Catheters have become increasingly useful in remote and difficult to reach locations within the body. However, the utilization of these catheters is frequently limited because of the need for the precise placement of the tip of the catheter at a specific location within the body.
Control of the movement of catheters to achieve such precise placement is difficult because of the inherent structure of a catheter. The body of a conventional catheter is long and tubular. To provide sufficient control of the movement of the catheter, it is necessary that its structure be somewhat rigid. However, the catheter must not be so rigid as to prevent the bending or curving necessary for movement through the vein, artery or other body part to arrive at the specified location. Further, the catheter must not be so rigid as to cause damage to the artery, vein or body part while it is being moved within the body.
While it is important that the catheter not be so rigid as to cause injury, it is also important that there be sufficient rigidity in the catheter to accommodate torque control, i.e., the ability to transmit a twisting force along the length of the catheter. Sufficient torque control enables controlled maneuverability of the catheter by the application of a twisting force at the proximal end of the catheter that is transmitted along the catheter to its distal end. The need for greater torque control often conflicts with the need for reduced rigidity to prevent injury to the body vessel.
Catheters are used increasingly for medical procedures involving the human heart. In these procedures a catheter is typically advanced to the heart through veins or arteries and then is positioned at a specified location within the heart. Typically, the catheter is inserted in an artery or vein in the leg, neck, upper chest or arm of the patient and threaded, often with the aid of a guidewire or introducer, through various arteries or veins until the tip of the catheter reaches the desired location in the heart.
The distal end of a catheter used in such a procedure is sometimes preformed into a desired curvature so that by torquing the catheter about its longitudinal axis, the catheter can be manipulated to a desired location within the heart or in the arteries or veins associated with the heart. For example, U.S. Pat. No. 4,882,777 discloses a catheter with a complex curvature at its distal end for use in a specific procedure in the right ventricle of a human heart. U.S. Pat. No. 5,231,994 discloses a guide catheter for guiding a balloon catheter for the dilation of coronary arteries. U.S. Pat. No. 4,117,836 discloses a catheter for the selective coronary angiography of the left coronary artery and U.S. Pat. Nos. 5,299,574, 5,215,540, 5,016,640 and 4,883,058 disclose catheters for use in selective coronary angiography of the right coronary artery. See also U.S. Pat. No. 4,033,031. Finally, U.S. Pat. No. 4,898,591 discusses a catheter with inner and outer layers containing braided portions. The '591 patent also discloses a number of different curvatures for intravascular catheters.
In addition to single catheters with various curvatures, U.S. Pat. No. 4,581,017 discloses an inner and outer guide catheter, (numbers 138 and 132), for use with a balloon catheter for treatment of coronary arteries. U.S. Pat. No. 5,267,982 discloses a catheter assembly and methods for catheterization of coronary arteries wherein an inner catheter (50) and outer catheter (52) are used in combination for the treatment of right and left coronary angiographic procedures. See also U.S. Pat. No. 4,935,017 which discloses a similar device. U.S. Pat. No. 5,290,229 discloses a straight outer sheath and a preformed inner catheter for use in the heart. See also U.S. Pat. Nos. 5,304,131, 5,120,323, 4,810,244 and 5,279,546.
Thus, there are a number of patents which disclose catheters with predetermined shapes, designed for use in specific medical procedures generally associated with the heart or the vascular system. Because of the precise physiology of the heart and the vascular system, catheters or introducers with carefully designed shapes for predetermined uses within the human heart and vascular system are important.
The sources of energy used for catheter ablation vary. Initially, high voltage, direct current (DC) ablation techniques were commonly used. However, because of problems associated with the use of DC current, radio frequency (R.F.) ablation has become a preferred source of energy for the ablation procedures. The use of RF energy for ablation has been disclosed, for example, in U.S. Pat. Nos. 4,945,912, 5,209,229, 5,281,218, 5,242,441, 5,246,438, 5,281,213 and 5,293,868. Other energy sources being considered for ablation of heart tissue include laser, ultrasound, microwave and direct current fulgutronization procedures. Also disclosed have been procedures where the temperature about the catherization probe is modified.
Catheter ablation of accessory pathways associated with Wolfe-Parkinson-White syndrome using a long vascular sheath by both a transseptal and retrograde approach is discussed in Saul, J. P., et al. "Catheter Ablation of accessory Atrioventricular Pathways in Young Patients: Use of long vascular sheaths, the transseptal approach and a retrograde left posterior parallel approach" Journal of the American College of Cardiology, Vol. 21, no. 3, pps. 571-583 (Mar. 1, 1993). See also Swartz, J. F. "Radiofrequency Endocardial Catheter Ablation of Accessory Atrioventricular Pathway Atrial Insertion Sites" Circulation, Vol. 87, no. 2, pps. 487-499 (February, 1993).
Accordingly, it is an object of this invention to prepare a dual guiding introducer system for selected medical procedures in the left atrium.
It is a further object of this invention to prepare a dual guiding introducer system for use in selected electrophysiology procedures within the left atrium of the heart.
Another object of this invention is to prepare a dual guiding introducer system for use in selected ablation procedures within the left atrium of the heart.
These and other objects are obtained by the design of the guiding introducer system disclosed in the instant invention.